package com.home.jinlanhua.utils;

import org.jetbrains.annotations.NotNull;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Set;

public class BeanUtils {

    public static void main(String[] args) {
        HashMap<String, String> map = new HashMap<>();
        map.put("a","b");
        System.out.println(map.toString().substring(1));
    }

    @NotNull
    private static String[] getNullPropertyNames(Object source) {
        final BeanWrapper src = new BeanWrapperImpl(source);
        java.beans.PropertyDescriptor[] pds = src.getPropertyDescriptors();

        Set<String> emptyNames = new HashSet<>();
        for(java.beans.PropertyDescriptor pd : pds) {
            Object srcValue = src.getPropertyValue(pd.getName());
            if (srcValue == null) emptyNames.add(pd.getName());
        }
        String[] result = new String[emptyNames.size()];
        return emptyNames.toArray(result);
    }

    public static void copyPropertiesIgnoreNull(Object source, Object target){
        org.springframework.beans.BeanUtils.copyProperties(source, target, getNullPropertyNames(source));
    }

}
